Possibly by having the service on-demand they have fewer liabilities so you don't go out of business if demand drops off, which is what did in US Helicopter. Helicopters as a Service.
On the other hand if they're too successful maybe the company they're chartering from could decide to offer service themselves and cut them out
Having it on-demand means they are possibly flying under FAA part 135 regs (charter/commuter) instead of 119 (scheduled carrier) so the expense might be a little lighter there.
That said, someone's got to pay the mortgage on a $2.6 million ship, plus fuel and maint and salaries etc etc.
They're not the carrier. From the bottom of the page:
Gotham Air is not a direct air carrier but rather provides technology and information services enabling consumers to obtain aircraft charter and shared aircraft charter services from FAA certified and DOT registered air carriers who exercise operational control over all flights .
Exactly I've seen a few services like this advertised exactly the same way (WSJ ads some run by former industry execs).
Interesting thought that the picture of the heli contradicts that (says "Gotham Air" on the side). That's no small point actually. Gives someone who doesn't read the fine print the idea that they do operate the aircraft. I understand why they do that but it is a bit deceptive.
Wouldn't the livery on that helicopter in the photo just be a form of corporate advertising. Couldn't you paint your aircraft however you want so long as the correct registration / licensing marks are visible?
A helicopter company is going to have a hard time hiring iOS developers and managing a software development project, not to mention the most important part: the brand.